Decide which expressIds the evaluator walks. Public for testability — consumers should only depend on the results returned, not on the iteration count, but a benchmark / regression test may want to assert the prefilter actually narrows.
Optional
Decide which expressIds the evaluator walks. Public for testability — consumers should only depend on the results returned, not on the iteration count, but a benchmark / regression test may want to assert the prefilter actually narrows.